A battery monitor integrated circuit (IC), which monitors a battery such as a lead battery and a lithium-ion battery, includes a voltage detection circuit of a fully-differential configuration for a detection operation for detecting a voltage of a battery. This voltage detection circuit has a function of an A/D converter. In such a battery monitor IC, a differential amplifier included in the A/D converter tends to consume more current for executing an A/D conversion operation at higher speed and with higher precision. Since an increase in a consumed current (current consumption) in the battery monitor IC leads to a variation in a state of charge (SOC) of the battery and an increase of heat generation of the IC, it is necessary to lower the current consumption.
Many conventional technologies are proposed for lowering current consumption of an A/D converter and the like. An intermittent operation will be most effective in an application, in which an A/D conversion is not executed continuously in, for example, a battery monitor IC. For example, in JP 2016-70903A, function blocks are operated intermittently for reducing power consumption.
The intermittent operation for reducing current consumption of the A/D converter will however potentially cause the following problem. That is, the A/D converter needs a stabilization period for stabilization of circuit states before restoring its operable state after stopping its operation once.
The stabilization period is, for example, a convergence period required for stabilization of an operation of a common feedback circuit, which controls a common mode level of an output voltage of an amplifier. In case that the A/D converter needs a comparatively long stabilization period from stopping to restoring its operation, such a stabilization period results in a wasteful wait period and delays a completion of a voltage detection operation.